Perioperative beta blockers may not benefit patients with diabetes (if not used properly)

BJM editorial note: "The DIPOM Trial randomized 921 diabetic patients to either 100 mg metoprolol (Toprol XL) or placebo, given from the day before surgery and continued for up to eight days. During a median follow-up of 18 months, all cause mortality, acute MI, unstable angina, or CHF occurred in 21% of the metoprolol group and 20% of the placebo group."

I took the liberty to add "if not used properly" to the title because the study did not follow the protocol for optimal use of beta blockers in the perioperative period of noncardiac surgery.

According to the protocol used at the Cleveland Clinic, beta blockers should be started at least 2 weeks before the surgery and continued for at least 2 weeks after the surgery.

In addition, as Dr. Aneja from the Section Hospital Medicine pointed out before, we believe that beta-blockers appear most likely to be beneficial in patients with a high RCRI (Relative Cardiac Risk Index >2) , i.e. not all patients will benefit from beta blockade in the perioperative period. Indeed, for some patients at low risk, beta blockers may even be harmful.

Revised Cardiac Risk Index (RCRI, Circulation. 1999;100:1043-1049):

Ischemic heart disease
History of congestive heart failure
History of cerebrovascular disease
Insulin therapy for diabetes
Preoperative serum creatinine >2.0 mg/dL

4CD is a mnemonic to remember the risk factors in RCRI:

CAD
CHF
CVA
CKD
DM

In the UK news: Beta-blockers not to be used to treat hypertension in most patients

The National Institute for Health and Clinical Excellence (NICE) and the British Hypertension Society (BHS) have issued new recommendations NOT to use beta-blockers to treat hypertension, except in a few specific cases. The rationale for the recomenndation was that beta-blockers are not more effective than ACEi and CCB and can carry a higher risk (up to 30%) of provoking type 2 diabetes. Beta-blockers should still be used in hypertensive patients with a previous MI or CHF.

References:
Perioperative blockade may not benefit patients with diabetes. BMJ.
Effect of perioperative blockade in patients with diabetes undergoing major non-cardiac surgery: randomised placebo controlled, blinded multicentre trial. BMJ.
Q&A: Beta-blockers. BBC.
Perioperative Beta-Blocker Therapy for Noncardiac Surgery. Medscape.com.
Image source: OpenClipArt.org, public domain

Updated: 03/31/2008

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